Device for increasing the impulsion of a fluid, especially applicable as a lift or propulsion device



July 12, 1960 J.- H. BERTIN ETAL 2,944,386

DEVICE FOR INCREASING THE IMPULSION OF A FLUID, ESPECIALLY APPLICABLE ASA LIFT OR PROPULSION DEVICE Filed June 25, 1957 INVENTORS a -Mu M JM 1B1Mafia-x), 8:4,, M v d/afiar ATTORNEYS DEVICE FOR INCREASING THEIMPULSION A V FLUID, ESPECIALLY APPLICABLE AS A LIFI OR PROPULSIONDEVICE Jean Henri Bel-tin, Neuilly sur-Seine, and Henri FrancoisSchmitt, Bourg la-Reine, France, assignors to Societe Bertin & Cie,Paris, France, a French company i Filed June 25, 1957, Ser. No. 667,8317 Claims priority, application France June 25, 1956 1 Claim. (Cl.60-355) In their patent application No. 624,811 of Nov. 28, 1956, nowPatent No. 2,922,277, the applicants have described a device forincreasing the impulsion of a flow of fluid which is especiallyapplicable as a lift or propulsion device for aircraft.

Thisapparatus is characterised by the combination of a convergenttubular member which brings the fluid up to speed and a divergentportion serving to reduce the convergent 1 is induced by the action ofthe fluid screen discharged from the slot 3. The divergent tube 5 isintended to channel the flow induced through the convergent 1 and thescreenissuing from the slot 3, when this screen, after a certain activetrajectory through the air, indicated by the arrows F and F, has lostthe greater part of its energy and therefore of its eifectiveness. I Thetube 5 then acts to relay this fluid screen in its action and improvesthe pressure coupling between the induced i jet and the atmosphere. Inaddition, this regularisation of. the induced flow is accompanied by anincrease in the quantity of this flow'which acts concurrently-m increasethe thrust produced. The tube 5 must be coupled to the fluid screen andin view of the large divergence of this screen (half-angle at the apexof,30, for example), its diameter at'the neck must be clearly greaterthan that of the, neck 2 of the convergent '1 (by, 'to 50%, for' 1example).

speed, the said portion being formed by a fluid screen produced by thedischarge of a fluid under pressure through a nozzle in the form of asuitably orientatedslotarranged on the solid convergent tubular member.

The present invention has for its object improvements made to thisdevice, in particular with a'view to rendering its use more convenient,more practical and more efiective. r

In accordance withthe invention, a solid divergent is provided at acertain distance from the convergent so as. i

v of a' jet, said nozzle extending along the periphery of to envelop andsustain the divergent fluid screen which,

at that distance, has lost a great part of its energy and in consequenceof its eflectiveness, this divergent having an intake section suitablyadapted to thatoflthe fluid 7 screen and greater than the neck of theconvergent from which it is separated by a space in which thefluidrscreen acts alone. a

In the accompanying drawings:

Fig. 1 shows in axial cross-section an impulsionincreasing devicecombined with a solid divergent.

Fig. 2 relates to an improvement in the lift device applicable to thecasein which the divergent fluid screen is formed'by a liquid.

In Fig. 1, there is seen at 1 the convergent of the lift deviceterminating at the neck 2 or very slightly on the certain distance by atubular divergent member '5, which 5 is usually fairly short, and whichis coupled to the convergent 1 by arms 6 and 6'. I This tube 5 maycomprise a small convergent 7.

from as a divergent jet, and a pump which sucks the liquid collected insaid vannular chamber and discharges downstream side of this neck, at 3the nozzle in the It will be assumed in this example that the flow inthe. i

Fig. 2"shows a lift device of this type, in which the fluid divergent isformed by a liquid passed into the collector 4. A ring 39.disposedcoaxially with the convergent 1 and provided with an annular slot 40recovers the liquid used for the fluid screen. v A pump'41' driven by amotor 42 brings back this liquid, under pressure, into the collector 4.

What is claimed is:

Jet augmenter comprising a convergent duct bounded by a physical walland ending with an orifice open tothe atmosphere, a pressure chamberintegral with said wall and extending outside said duct in the vicinityof said orifice, means for supplying pressure liquid to said chamber, aslot-like nozzle communicating with said chamber'and adapted todischargesaid liquid in the form said orifice and facing in a directiondiverging slightly 1 from the axis of said duct whereby the jet issuingvfrom, said nozzle forms a divergent liquid wall extending the convergentphysical wall of the duct and bathed by the atmosphere, a divergent ductbounded by a physical wall and substantially coaxial with the convergentduct, said divergent duct extending at a distance downstream of theconvergent duct and around the path of the divergent .jet, an annularchamber formed on said divergent duct and having an annular: inlet.facing towards said slot-like,

nozzle in order to collect part ofthe liquid issuing thereit into saidpressure chamber.

References Cited in the file of this patent Germany July 4, 1910

